I received an RMA email minutes after chat with the Sonos agent. The link to initiate the process failed to complete.
A follow-up chat about the problem led to an escalation to the 'returns team'. I was told I would receive a reply within 24-48 hrs.
Almost a week later and I'm still waiting...
My problem is compounded by having to use the chat support (due to a speech impediment which makes phone support almost impossible).
I sort of expected better practical support from Sonos.